Mobile devices such as mobile communication terminals are equipped with a variety of functions and accordingly provide combined operations. Examples of the functions are a voice call, text message transmission/reception, digital broadcast reception, audio file playback, and such. In order to control and execute the functions, the mobile devices are equipped with input devices. The input devices may be implemented with various types of devices, such as button keypads, touch screens, touch pads, ball joysticks, optical joysticks, wheel keys, trackballs, and such. Most mobile devices tend to employ full touch screens as input devices that provide user convenience.
Conventional touch screens only allow for the user's direct touches to perform corresponding functions. This user's touch motion blocks a portion of the touch screen, so the user cannot touch a correct point, which causes the mobile device to malfunction. Therefore, new input devices need to be developed.
Mobile devices can perform multi-tasking by simultaneously executing a number of applications. Although mobile devices execute many applications, they cannot display the executed applications on one screen. This is because the screen size is limited. Therefore, in order to execute applications, a mobile device must switch between corresponding screens. For example, when an alarm event occurs in the mobile device while the device is reproducing a broadcast, it requires the user to switch the broadcast screen to the alarm screen and then touch the screen to release the alarm. Since conventional mobile devices control a number of executed applications via only one input device (e.g., a touch screen), it makes the user feel inconvenienced.